Because the Department of Defense was originally involved in the design, many falsely think that ARPANET was started to create a network that would survive a nuclear attack. It was originally designed for researchers - who were far away from resources - to access high performance computers. Later on in the project, ARPANET work focused on redundancy and survivability in the event of a large scale attack on the United States.

One of the key developers for ARPANET was an engineer named Paul Baron. Here's a few quotes pulled from a New York Times piece about Paul:

In the early 1960s, while working at the RAND Corporation in Santa Monica, Calif., Mr. Baran outlined the fundamentals for packaging data into discrete bundles, which he called “message blocks.” The bundles are then sent on various paths around a network and reassembled at their destination. Such a plan is known as “packet switching.”

Mr. Baran’s idea was to build a distributed communications network, less vulnerable to attack or disruption than conventional networks. In a series of technical papers published in the 1960s he suggested that networks be designed with redundant routes so that if a particular path failed or was destroyed, messages could still be delivered through another.

Mr. Baran’s invention was so far ahead of its time that in the mid-1960s, when he approached AT&T with the idea to build his proposed network, the company insisted it would not work and refused.

Here's more from the New York Times piece:

Paul Baran was born on April 29, 1926, in Grodno, Poland. His parents moved to the United States in 1928, and Mr. Baran grew up in Philadelphia. His father was a grocer, and as a boy, Paul delivered orders to customers in a small red wagon.

He attended the Drexel Institute of Technology, which later became Drexel University, where he earned a bachelor’s degree in electrical engineering in 1949.

He went on to complete is Masters Degree in Electrical Engineering at UCLA in 1959. In 1959 he also joined the computer science department at RAND, a nonprofit global policy think tank first formed to offer research and analysis to the United States armed forces. In 1968, Baron left RAND to co-found a nonprofit research organization that specialized in long-tern technology forecasting called the Institute for the Future. Along the way he also started seven companies.

Google vice-president, colleague and longtime friend Vinton Cerf had a nice quote about Paul in that New York Times piece:

Paul wasn’t afraid to go in directions counter to what everyone else thought was the right or only thing to do, AT&T repeatedly said his idea wouldn’t work, and wouldn’t participate in the Arpanet project,

In 2001, I was selected as one of the top 15 STEM faculty in the United States by Microsoft and the American Association of Community Colleges and in 2004 was selected as the Massachusetts Network and Communications Council Workforce Leader of the year.